POWERPC: Set dma_data correctly for direct_ops on pasemi

More late-caught fallout from the mainline merge.  Commit
35e4a6e2

 ("[POWERPC] Use
archdata.dma_data in dma_direct_ops and add the offset") claimed

  "Now that all platforms using dma_direct_offset setup the
   archdata.dma_data correctly, ..."

..but nope -- the pasemi iommu setup code that disables translation on
the DMA pci device didn't set dma_data correctly.

This fixes it.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>